Comparison of the sedative effects of nalbuphine and butorphanol, alone or in combination with acepromazine in dogs.

Objective: To compare sedation and effects on heart rate (HR), mean arterial pressure (MAP) and respiratory rate (f) of nalbuphine and butorphanol, alone or combined with acepromazine in dogs.

Study Design: Prospective, randomized experimental trial.

Animals: Eight healthy Beagle dogs, aged (mean ± standard deviation) 3.4 ± 0.5 years and weighing 11.0 ± 1.3 kg.

Methods: Each dog was treated four times: physiological saline (1 mL) combined with nalbuphine (0.5 mg kg; SAL-NAL) or butorphanol (0.15 mg kg; SAL-BUT), and acepromazine (0.05 mg kg) combined with nalbuphine (0.5 mg kg; ACP-NAL) or butorphanol (0.15 mg kg; ACP-BUT), intravenously (IV). The degree of sedation, assessed by a numeric descriptive scale (NDS) and simple numerical scale (SNS), HR, MAP, f and rectal temperature (RT), were recorded before and 20 minutes after administration of saline or acepromazine, then 15, 30, 60, 90 and 120 minutes after nalbuphine or butorphanol. Values were compared with baseline and among treatments.

Results: Mild sedation was recorded for SAL-NAL and SAL-BUT, and moderate sedation for ACP-NAL and ACP-BUT. NDS and SNS scores were higher for SAL-BUT and ACP-BUT at some time points when compared with SAL-NAL and ACP-NAL, respectively (p < 0.001). HR was lower in ACP-NAL than in ACP-BUT at 120 minutes and f was lower in SAL-BUT than in SAL-NAL at 30 and 120 minutes (p < 0.05). RT was lower in SAL-BUT (37.5 ± 0.5 °C) compared with SAL-NAL (38.0 ± 0.5 °C) at 60-120 minutes (p < 0.05).

Conclusions And Clinical Relevance: Butorphanol promoted a higher sedative effect than nalbuphine when alone and combined with acepromazine. IV administration of nalbuphine or butorphanol, with or without acepromazine, at the doses studied, resulted in minimal decreases in MAP, HR, f and RT.